Table of Contents
- 1 Is the variance of a random variable X is 23 then what is the variance of 2x 10?
- 2 What is the variance of random variable of X?
- 3 What is the variance of a random variable used for?
- 4 How do you find the variance of a random variable?
- 5 How do you find the variance of a discrete random variable?
- 6 How do you find the standard deviation of a random variable?
Is the variance of a random variable X is 23 then what is the variance of 2x 10?
If a variance of a random variable x is 23 ,then what is the variance of 2x 10? (a)56 (b)33 (c)46 (d)92 Correct answer is ‘D’.
What is the variance of random variable of X?
For a discrete random variable X, the variance of X is obtained as follows: var(X)=∑(x−μ)2pX(x), where the sum is taken over all values of x for which pX(x)>0. So the variance of X is the weighted average of the squared deviations from the mean μ, where the weights are given by the probability function pX(x) of X.
What is the variance of X equal to?
Definition. In other words, the variance of X is equal to the mean of the square of X minus the square of the mean of X.
What is the expected value of the sum of two random variables?
The expected value of the sum of several random variables is equal to the sum of their expectations, e.g., E[X+Y] = E[X]+ E[Y] . On the other hand, the expected value of the product of two random variables is not necessarily the product of the expected values.
What is the variance of a random variable used for?
A measure of spread for a distribution of a random variable that determines the degree to which the values of a random variable differ from the expected value.
How do you find the variance of a random variable?
To calculate the Variance:
- square each value and multiply by its probability.
- sum them up and we get Σx2p.
- then subtract the square of the Expected Value μ
How do you find e X2?
The expected value of X is usually written as E(X) or m. So the expected value is the sum of: [(each of the possible outcomes) × (the probability of the outcome occurring)]. In more concrete terms, the expectation is what you would expect the outcome of an experiment to be on average.
How do you calculate expected sum?
How do you find the variance of a discrete random variable?
Variance of a Discrete Random Variable The variance of a discrete random variable is given by: σ 2 = Var (X) = ∑ (x i − μ) 2 f (x i) The formula means that we take each value of x, subtract the expected value, square that value and multiply that value by its probability.
How do you find the standard deviation of a random variable?
The standard deviation of a random variable, X, is the square root of the variance. Consider the first example where we had the values 0, 1, 2, 3, 4. The PMF in tabular form was: Find the variance and the standard deviation of X. SD ( X) = 2 ≈ 1.4142 Click on the tab headings to see how to find the expected value, standard deviation, and variance.
What is the value of V(2x + 10) = 92?
In nutshell, V (aX+b) = a 2 V ( X). And using this, one may easily see that V ( 2 X + 10) = 4 V ( X) = 92. I am sorry, I didn’t notice the answer given by Koushiki Ma’am. Her answer is perfect and beautifully explained.
What is the standard deviation of 2x-5?
Variance is the square of the standard deviation. Because the standard deviation of x is 5, the variance of x is 25. So the variance of 2x is (2²) (25), or 100. So the variance of 2x-5 would also be 100. Not that you asked, but this would make the standard deviation of 2x = √100 or 10.